This has been discussed several times on soci-users: http://sourceforge.net/mailarchive/message.php?msg_id=21455333 (search for "sequence")
http://sourceforge.net/mailarchive/message.php?msg_id=21032224 http://sourceforge.net/mailarchive/message.php?msg_id=24476114 Long story short, there was some resistance from Maciej and others and the feature never got implemented. FWIW i would have no objection to implementing such feature. I personally don't think it would be useful since I don't believe in cross-database portability, but I don't think there would be any harm in implementing it. Thanks, Aleksander On Fri, May 25, 2012 at 5:35 AM, Vadim Zeitlin <[email protected]> wrote: > Hello, > > It is common to use auto-generated values for primary keys of the tables > that don't have any natural candidate. There are 2 mechanisms for doing > this depending on the database: > > 1. Use a sequence. In this case you need to get the next value from the > sequence and use it in "INSERT INTO" statement explicitly. > > 2. Use "auto increment field. In this case you don't need to, and at least > in MS SQL case, actually can't (unless you turn off identity insert > option), specify the value for the field when inserting it and it's > automatically generated by the database instead. > > > Firebird, Oracle, PostgreSQL and several others support (1) while MS SQL > and MySQL (and maybe others too) support (2). This makes writing the code > meant to work with different RDBMS a bit difficult but it may still be > done. In pseudo code: > > statement = "INSERT INTO T(F1, F2) VALUES(?, ?)"; > id_value = get_next_sequence_value("sequence_name"); > if id_value != -1: > statement = "INSERT INTO T(ID, F1, F2) VALUES(?, ?, ?)"; > statement.use(id_value) > > statement.execute() > > if id_value == -1: > id_value = get_last_insert_id("tale_name") > > > The problem is that currently SOCI doesn't provide the required > get_next_sequence_value() and get_last_insert_id() functions. I could > implement them myself using get_backend() but I think that it would really > make more sense to have them inside SOCI itself as the implementation is > entirely backend-specific. What do you think? > > I'd be able to do it for all the existing backends except SQLite (it > should be possible to implement it there as well using the information from > http://www.sqlite.org/autoinc.html but we don't use SQLite so I don't > really need it there). ODBC one is special because the mechanism to use > depends on the driver used, so I'd need to call SQLGetInfo(SQL_DBMS_NAME) > and check it dynamically. If anybody has any ideas about how to do it > better, I'd like to know about it, of course. > > Thanks in advance for any comments/ideas, > VZ > > ------------------------------------------------------------------------------ > Live Security Virtual Conference > Exclusive live event will cover all the ways today's security and > threat landscape has changed and how IT managers can respond. Discussions > will include endpoint security, mobile security and the latest in malware > threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ > _______________________________________________ > Soci-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/soci-users > ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Soci-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/soci-users
